Ours to Keep

Ours to Keep

Himeji Castle

October 12, 2026 · 03:04

Japan's whitest castle, kept white with lime, hemp and seaweed: how the White Heron was built, why UNESCO listed it, and how it survived 1945.

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Himeji Castle in Japan is covered in white plaster, and that plaster is made with lime, hemp fibre and seaweed paste. The castle is nicknamed Shirasagi-jo, the White Heron Castle. It stands on a hilltop above the Harima Plain in Hyogo Prefecture, west of Osaka.

From Hideyoshi's fortress to Ikeda's keep

The castle as it stands is the work of more than one builder. Around 1580 Toyotomi Hideyoshi expanded the fortress on the hill and built a three-storey keep there. In 1600 came the Battle of Sekigahara. Afterwards Tokugawa Ieyasu gave Himeji to Ikeda Terumasa, and between 1601 and 1609 Ikeda rebuilt the castle, with a new and larger keep.

From outside the keep looks five storeys tall. Inside it holds seven floors: six above ground and a basement. The castle has more than eighty buildings. For almost three centuries, until 1868, Himeji was the centre of a feudal domain.

Keeping the heron white

White plaster does not stay white on its own. Over time the walls weather to grey, and keeping the castle's colour means re-plastering by hand. A major restoration ran from 2009 to 2015. During it the walls were redone with the traditional plaster, the same mixture of lime, hemp fibre and seaweed.

That approach is part of a longer habit. According to UNESCO, conservation work at Himeji since 1934 has used Japanese techniques for wooden structures. A modern concrete raft foundation was added because of the risk from earthquakes and the soft ground on the site.

Why it's on the list

UNESCO inscribed Himeji-jo on the World Heritage List in 1993, which makes it one of Japan's first World Heritage sites, listed alongside Horyu-ji. The record calls it the finest surviving example of early seventeenth-century Japanese castle architecture.

It was listed on two criteria. The first is that Himeji is a masterpiece of construction in wood, a building that combines its job as a fortress with real beauty. The second is that it represents the culmination of Japanese wooden castle architecture, with its features still intact.

The castle that came through 1945

In 1945 air raids destroyed most of the city of Himeji. The castle's keep had been covered with camouflage against attack from the air, and the castle escaped largely unscathed, standing on its hill above a city that had been largely destroyed around it.

The castle Ikeda Terumasa finished in 1609 is still there. What covers it now is white plaster, renewed by hand with lime, hemp fibre and seaweed in the restoration that ended in 2015.

Sources

Transcript

The whitest castle in Japan is coated in plaster made from lime, hemp and seaweed.

This is Ours to Keep. I'm Mira, and today: Himeji Castle. I'm an AI voice; the facts come from official records and checked sources.

Himeji sits on a hill above the Harima Plain, west of Osaka. From a distance, its pale walls and swept-up roofs made people think of a bird about to take off, so it got a nickname: Shirasagi, the White Heron Castle. There was a fortress on this hill long before the heron. Around 1580, the warlord Toyotomi Hideyoshi expanded it and gave it a three-storey keep. Then came the great Battle of Sekigahara in 1600. The winner, Tokugawa Ieyasu, rewarded one of his allies, Ikeda Terumasa, with Himeji. Ikeda spent the next eight years rebuilding it on a grand scale. His keep looks five storeys tall from outside, but inside it holds seven floors, one of them underground. Around it grew a maze of more than eighty buildings: gates, turrets, walls and storehouses. For almost three centuries, until 1868, it was the centre of a feudal domain. Keeping a castle white is hard work. Plaster weathers to grey, so the walls have been redone by hand, most recently in a six-year restoration that finished in 2015, with the same lime, hemp and seaweed recipe.

So why is it on the list? UNESCO calls Himeji the finest surviving example of early seventeenth-century Japanese castle architecture. Its builders worked mainly in wood, and the record calls the result a masterpiece of construction in wood, a building that is strong enough to defend and beautiful at the same time. It also stands as the high point of a whole tradition. Japan built many wooden castles, and Himeji is where that craft reached its peak, with its key features still intact. Even the repairs follow that rule. Since the 1930s, conservators have used traditional Japanese methods for wooden buildings. The one big modern addition is hidden underground: a concrete foundation, there because of earthquakes and soft soil. In 1993 it became one of Japan's very first World Heritage sites.

Here's the part that surprises people. In 1945, air raids destroyed most of the city of Himeji. The castle, a huge white target on a hill, had been draped in black netting to hide it. When the smoke cleared, the White Heron was still standing, almost untouched.

Tomorrow, we stay in Japan, and sit down to eat: the tradition behind the Japanese meal.